As is known, in order to dispense different gases and particularly medical oxygen it is necessary to provide a device which allows to adjust the flow-rate of the fluid that is dispensed.
The solutions of the background art generally provide rotating disks which are polygonally coupled to a rotating rod, connected to a handwheel which allows to turn the disk so as to place at least one of the provided calibrated holes at a product delivery port.
Such known solutions suffer problems of deformation and crushing of the disk during rotation; moreover, with known solutions the rotating disk may arrange itself so that no holes are located at the output port and therefore the output flow may even be interrupted, with the consequent severe problems, in view also of the fact that the user might be a patient who is alone and is suffering a respiratory crisis.